What is the immediate management for a patient with new onset seizure?

Immediate Management of New Onset Seizure

For an adult patient with new onset seizure who has returned to baseline, immediately check serum glucose and sodium levels, obtain a pregnancy test if the patient is a woman of childbearing age, and perform neuroimaging when feasible in the emergency department. 1, 2

Initial Stabilization and Assessment

Ensure airway protection and assess for ongoing seizure activity first. 3 If the patient has not returned to baseline mental status, persistent altered consciousness, or focal neurologic deficits, this requires more extensive and urgent evaluation. 1, 2

Essential Laboratory Testing

For patients who have returned to baseline neurologic status:

• Serum glucose: Hypoglycemia is the most common metabolic cause, though rare (only 1-2 unexpected cases per 100-250 patients in prospective studies). 1, 2, 4
• Serum sodium: Hyponatremia is the second most frequent abnormality identified. 1, 2
• Pregnancy test for all women of childbearing age: This affects testing decisions, disposition, and antiepileptic drug selection. 1, 2

Additional laboratory tests (CBC, comprehensive metabolic panel, calcium, magnesium) should only be obtained when suggested by specific clinical findings such as fever, persistent altered mental status, known renal disease, malnutrition, or diuretic use. 2, 5 The yield of routine extensive laboratory testing is extremely low in otherwise healthy patients who have returned to baseline. 1, 6

Neuroimaging

Perform a head CT scan in the emergency department when feasible, particularly if any high-risk features are present. 1, 2 High-risk features include:

• Age over 40 years 1
• History of acute head trauma 1
• History of malignancy or immunocompromised state 1, 2
• Anticoagulation use 1
• Persistent headache 1
• Focal neurologic examination or focal onset seizure 1, 2
• Fever 1, 2
• Persistent altered mental status 2

Deferred outpatient neuroimaging with MRI is acceptable for low-risk patients who have returned to baseline, have a normal neurologic examination, and have reliable follow-up arrangements. 1, 2 However, 22% of patients with normal neurologic examinations still have abnormal imaging, so this decision requires careful consideration of follow-up reliability. 2

Lumbar Puncture Indications

Lumbar puncture is NOT routinely indicated for uncomplicated first-time seizures. 2 Perform lumbar puncture (after head CT) only when:

• The patient is immunocompromised 1, 2
• There is fever with concern for meningitis or encephalitis 1, 2
• Signs of meningeal irritation are present 5

Disposition Decisions

Emergency physicians need not admit patients with a first unprovoked seizure who have returned to their clinical baseline in the emergency department. 2 Consider admission only if:

• Persistent abnormal neurologic examination 2
• Abnormal investigation results requiring inpatient management 2
• Patient has not returned to baseline 2
• Unreliable follow-up 1

The risk of seizure recurrence within 24 hours is 19% overall, but only 9.4% in nonalcoholic patients without focal CT lesions. 2 The mean time to first recurrence is 121 minutes (median 90 minutes), with 85% occurring within 6 hours. 2

Antiepileptic Drug Initiation

Do not routinely start antiepileptic drugs in the emergency department for a single first-time seizure. 2 Antiepileptic drug treatment reduces 1-2 year recurrence risk but does not affect long-term recurrence rates or remission rates, and exposes patients to medication adverse effects without proven mortality or morbidity benefit. 2

Defer the decision to start antiepileptic drugs to outpatient neurology follow-up, where risk stratification can be performed using EEG and detailed MRI. 7, 6, 8

Critical Pitfalls to Avoid

• Do not assume alcohol withdrawal seizure without excluding other causes, especially in first-time seizures—this should be a diagnosis of exclusion. 1, 5
• Do not miss structural lesions: 22-41% of first-time seizure patients have abnormal CT findings, and some require urgent intervention. 1, 2
• Do not perform extensive laboratory testing in patients who have returned to baseline with normal examination—the yield is extremely low and most abnormalities are predicted by history and physical examination. 1, 5
• Do not forget pregnancy testing in women of childbearing age—this fundamentally changes management. 1

Special Populations

For immunocompromised patients (including HIV-positive patients): Perform head CT followed by lumbar puncture either in the emergency department or after admission, as 40% may have acute lesions requiring admission. 1, 2